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Research News

Bybee, S.M., Kalkman, V.J., Erickson, R.J., Frandsen, P.B., Breinholt, J.W., Suvorov, A., Dijkstra, K.-D.B., Cordero-Rivera, A., Skevington, J.H., Abbott, J.C., Sanchez Herrera, M., Lemmon, A.R., Moriarty Lemmon, E., Ware, J.L. 2021. Phylogeny and classification of Odonata using targeted genomics. Molecular Phylogenetics and Evolution 160: 107115.

A new family of damselfly described by Dr. John Abbott.
A new family of damselfly described by Dr. John Abbott.

Dragonflies and damselflies are a charismatic, medium-sized insect order (~6300 species) with a unique potential to approach comparative research questions. Their taxonomy and many ecological traits for a large fraction of extant species are relatively well understood. However, until now, the lack of a large-scale phylogeny based on high throughput data with the potential to connect both perspectives has precluded comparative evolutionary questions for these insects. Here, we provide an ordinal hypothesis of classification based on anchored hybrid enrichment using a total of 136 species representing 46 of the 48 families or incertae sedis, and a total of 478 target loci. Our analyses recovered the monophyly for all three suborders: Anisoptera, Anisozygoptera and Zygoptera. Although the backbone of the topology was reinforced and showed the highest support values to date, our genomic data was unable to stronglyresolve portions of the topology. In addition, a quartet sampling approach highlights the potential evolutionary scenarios that may have shaped evolutionary phylogeny (e.g., incomplete lineage sorting and introgression) of this taxon. Finally, in light of our phylogenomic reconstruction and previous morphological and molecular information we proposed an updated odonate classification and define five new families (Amanipodagrionidae fam. nov., Mesagrionidae fam. nov., Mesopodagrionidae fam. nov., Priscagrionidae fam. nov., Protolestidae fam. nov.) and reinstate another two (Rhipidolestidae stat. res., Tatocnemididae stat. res.). Additionally, we feature the problematic taxonomic groupings for examination in future studies to improve our current phylogenetic hypothesis.

Klompmaker, A.A. and Landman, N.H. 2021. Octopodoidea as predators near the end of the Mesozoic Marine Revolution. Biological Journal of the Linnean Society.

Late Cretaceous bivalve specimen showing an octopod hole.
Late Cretaceous bivalve specimen showing an octopod hole.

Octopodoidea are a highly versatile and diverse group of marine predators comprising > 200 species today, but their diversity and ecology in deep time are virtually unknown. Because these soft-bodied cephalopods have a low preservation potential, only a single body fossil species has been documented. Unlike other modern cephalopods, octopodoids leave behind a characteristic drill hole on their molluscan and crustacean prey. These traces provide a means to track their presence and behavior in deep time. Although severely understudied, some of such holes have been documented from the Eocene–Pleistocene fossil record. We document the oldest recognized drill holes attributed to octopodoids, found in lucinid bivalves from the Late Cretaceous (Campanian) of South Dakota, USA. These observations demonstrate that the drilling habit of these animals evolved early in the evolutionary history of Octopodoidea, ~25 million years earlier than was previously known. The drilled lucinids lived in cold methane seeps in the Western Interior Seaway. These predation traces have never been found in fossil seeps previously, thus adding a new predator to the food web of cold seeps. Finally, our results provide direct evidence that Octopodoidea were an integral component of the rise of shell-destroying predators during the Mesozoic Marine Revolution. Read the press release here.

Klompmaker, A.A. and Kittle, B.A. 2021. Inferring octopodoid and gastropod behavior from their Plio-Pleistocene cowrie prey (Gastropoda: Cypraeidae). Palaeogeography, Palaeoclimatology, Palaeoecology 564: 110251.

Example of a fossil cowrie specimen from Florida drilled by an octopus.
Example of a fossil cowrie specimen from Florida drilled by an octopus.

Predation is an evolutionary force shaping sea floor communities, with the record of drilling predation being particularly useful to study predatory behavior on short and long timescales. Most predatory drill holes are caused by gastropods, but octopods within Octopodoidea also produce characteristic drill holes, yet remain severely understudied in deep time. Consequently, studies comparing octopodoid versus gastropod drill holes from the same prey group are exceedingly rare. Cypraeid gastropod (cowries) are commonly drilled by octopodoids today, but nothing is known about drill holes produced by octopodoids and gastropod in fossil cypraeids. We studied 2406 Plio-Pleistocene fossil cowries from southern Florida, USA. Drilling by octopodoids was common (13.4% of specimens), whereas gastropod drill holes were rare (0.2%). There is strong site selectivity: most octopodoid drill holes are found in the ventral-left-posterior and ventral-left-middle shell regions. These parts are not the thinnest region of the shell, but represent the location where the columellar muscle anchors the soft tissue to the shell interior. We suggest that the octopodoids sought to paralyze and relax this muscle via the drill hole to minimize the time to consumption. Specimens with multiple octopodoid drill holes (24.1% of drilled specimens) have a higher proportion of drill holes located outside the ventral-left-posterior and ventral-left-middle regions. Thus, drilling outside these regions appears less effective. The few gastropod drill holes occur on the dorsal side. A meta-analysis shows that octopodoids produce significantly more drill holes per drilled molluscan shell than do gastropod drillers. We found mixed evidence for size selectivity: whereas the size of drilled specimens does not significantly differ from non-drilled specimens, drill-hole size is significantly larger in larger cowries, which may imply they were drilled by larger octopodoid individuals. We suggest that the molluscan fossil record should be leveraged to further study the evolution of octopodoid predation and behavior.

Klompmaker, A.A., Starzyk, N., Fraaije, R.H.B., and Schweigert, G. 2020. Systematics and convergent evolution of multiple reef-associated Jurassic and Cretaceous crabs (Decapoda, Brachyura). Palaeontologia Electronica 23(2): a32.

Carapace of the crab named after Dr. Cristina Robins: Eodromites cristinarobinsae. Scale bar: 1.0 mm.

We studied multiple true crabs (Brachyura) from primarily sponge and coral reefs that lived during the Jurassic and Cretaceous periods (201 to 66 million years ago). Both environments were important habitats for the evolution and biodiversity of crabs during the Late Jurassic epoch (164 to 145 million years ago). The central portion of the crabs, called the carapace, is used to study these crabs. We described one new genus and five new species. One species was named after UA Museums Research Associate Dr. Cristina Robins. Other taxa are redescribed in more detail, synonymized (four species), or reassigned (three species and two genera). After studying details of the carapace of closely and distantly related groups of crabs, we found similarities and differences among distantly related groups. The similarities in the rostrum might be a sign of their independent adaptation or convergent evolution in this context. In one case, we found very strong similarities between specimens of genera that were placed in two different superfamilies. We placed these taxa in the same family again and argue against extreme convergent evolution. We also report on a remarkably large parasitic swelling made by an isopod in one crab’s gill region, and we show the largest complete Jurassic crab carapace reported thus far.


Kiel, S., Hybertsen, F., Hyžný, M., and Klompmaker, A.A. 2020. Mollusks and a crustacean from early Oligocene methane-seep deposits in the Talara Basin, northern Peru. Acta Palaeontologica Polonica 65: 109–138.

Ghost shrimp claw.
Ghost shrimp claw.

Methane seeps are places on the ocean floor where methane escapes from the subsurface into the water column. Such seeps, also called cold seeps, can be found at different depths in the oceans today and in the past. They are essentially the cold equivalent of hydrothermal vents. Bacteria and other organisms, such as clams and tube worms living in symbiosis with these bacteria, feed on this methane and create local hotspots of biodiversity. Seeps attract a variety of organisms such as fishes, gastropods, echinoderms, and crustaceans. Research on modern and fossil methane seeps has been booming over the last decade. We report on a ~30 million-year-old seep fauna from Peru. We describe 25 species of bivalves, gastropods, and crustaceans, bringing the total local seep fauna close to 40 species. Among those species, six species (2 bivalves, 3 gastropods, and 1 ghost shrimp) and one genus are new to science. Many genera in this hotspot of biodiversity can also be found in the northeastern Pacific around that time, showing a biogeographic connection to that area.

Wallaard, J.J.W., Fraaije, R.H.B., Jagt, J.W.M., Klompmaker, A.A., and Van Bakel, B.W.M. 2020. The first record of a paguroid shield (Anomura, Annuntidiogenidae) from the Miocene of Cyprus. Geologija 63: 93–99.

Hermit crab shield.
Hermit crab shield.

Fossil hermit crabs (Paguroidea) have long been known from the fossil record, primarily from claws. Over the last ten years, their millimeter-sized shields (particularly the anterior part) have been increasingly recognized. As a result, researchers have since described over 30 new species from the Late Jurassic and mid-Cretaceous (~160–100 million years ago), particularly from coral reefs. Hermit crab shields were unknown from the Miocene (23–5 million years ago) until this paper. Fraaije and Klompmaker did field work in 2017 in ~10 million old fossil reefs exposed on Cyprus (eastern Mediterranean Sea) and found one shield of a paguroid. This shield represents a new hermit crab species, named Paguristes joecollinsi. This is just the first species from a rich crustacean reef fauna, so stay tuned for more papers in years to come!

Ehret, D. and Harrell, Jr., T.L. 2018. Feeding traces on Pteranodon (Reptilia: Pterosauria) bone from the late Cretaceous (Campanian) Mooreville Chalk in Alabama, USA. PALAIOS 33: 414–418.

A) Close-up picture of scavenging marks present on the ventral surface of ALMNH 8630. B) Partial dentary of Saurodon leanus, ALMNH 5101, demonstrating the size and spacing of the teeth in relation to the darker brown scavenging marks. Scale bars = 1 cm.
Pterosaur remains are exceptionally rare in the Late Cretaceous marine chalks of Alabama and the few specimens found are typically very fragmentary. We report the occurrence of a metacarpal of Pteranodon cf. longiceps from the Mooreville Chalk (Campanian, 83 million years old) of Dallas County, Alabama.

The Pteranodon specimen exhibits serrated teeth marks on the surface of the bone and a second set of larger, unserrated teeth marks unlike those of any contemporary shark species. These feeding traces compare favorably with the tooth spacing and morphology of Squalicorax kaupi, and a small to moderate-sized saurodontid fish, such as Saurodon or Saurocephalus, respectively. In both instances, feeding traces appear to be scavenging events due to the lack of any healing or bone remodeling. During the Campanian, Dallas County, Alabama, was a shallow-marine environment comprising part of the Mississippi Embayment. It is hypothesized that the specimen represents a pterosaur that either fell into marine waters or was washed out from nearshore areas and then scavenged by both a chondrichthyan and osteichthyan. This type of scavenging behavior has been recorded on other taxonomic groups from Alabama during the Late Cretaceous. However, the fragile, hollow bones of pterosaurs make their preservation rare.

Abbott K.K., John C. Abbott, Jeffrey D. Lozier, Rochelle R Beasley & Stacey L. Lance (2018) Development of polymorphic microsatellite markers for a rare dragonfly, Cordulegaster sarracenia (Odonata: Cordulegastridae), with notes on population structure and genetic diversity. International Journal of Odonatology 21: 165171.

We isolated and characterized a total of 13 microsatellite loci from Cordulegaster sarracenia (Odonata: Cordulegastridae). Loci were screened in 24 individuals from Louisiana and Texas. Within C. sarracenia, the number of alleles per locus ranged from 0 to 5, and observed and expected heterozygosities ranged from 0.000 to 0.556 and 0.000 to 0.613, respectively. Overall differentiation among study populations was very high (FST = 0.423), suggesting significant geographic population structure with low diversity within populations. Twelve of the 13 primers amplified in C. sayiC. diastatopsC. maculata, and C. obliqua and polymorphism levels are reported. These new genetic markers will provide tools for addressing a number of population genetic and demographic questions relating to conservation of this rare dragonfly species.

Field, D.J., Hanson, M., Burnham, D., Wilson, L.E., Super, K., Ehret, D., Ebersole, J., and Bhullar, B.-A.S., 2018. Complete Ichthyornis skull illuminates mosaic assembly of the avian head. Nature 557: 96100. 

The skull of living birds is greatly modified from the condition found in their dinosaurian antecedents. Bird skulls have an enlarged, toothless premaxillary beak and an intricate kinetic system that includes a mobile palate and jaw suspensorium. The expanded avian neurocranium protects an enlarged brain and is flanked by reduced jaw adductor muscles. However, the order of appearance of these features and the nature of their earliest manifestations remain unknown. The Late Cretaceous toothed bird Ichthyornis dispar sits in a pivotal phylogenetic position outside living groups: it is close to the extant avian radiation but retains numerous ancestral characters. Although its evolutionary importance continues to be affirmed, no substantial new cranial material of I. dispar has been described beyond incomplete remains recovered in the 1870s. Jurassic and Cretaceous Lagerstätten have yielded important avialan fossils, but their skulls are typically crushed and distorted. Here we report four three-dimensionally preserved specimens of I. dispar— including an unusually complete skull—as well as two previously overlooked elements from the Yale Peabody Museum holotype, YPM 1450.

A full 3D reconstruction of the skull of I. dispar is shown on the left. High-resolution scans of the right 11th mandibular tooth of YPM 1450 are shown on the right.

We used these specimens to generate a nearly complete three-dimensional reconstruction of the I. dispar skull using high resolution computed tomography. Our study reveals that I. dispar had a transitional beak—small, lacking a palatal shelf and restricted to the tips of the jaws—coupled with a kinetic system similar to that of living birds. The feeding apparatus of extant birds therefore evolved earlier than previously thought and its components were functionally and developmentally coordinated. The brain was relatively modern, but the temporal region was unexpectedly dinosaurian: it retained a large adductor chamber bounded dorsally by substantial bony remnants of the ancestral reptilian upper temporal fenestra. This combination of features documents that important attributes of the avian brain and palate evolved before the reduction of jaw musculature and the full transformation of the beak.